Means of producing hipersil cores to facilitate mounting thereof



Sept. 29, 1959 L MEANS OF PRODUCING HIPE MEANS OF PRODUCING HIPERSILCORES TO FACILITATE MOUNTING THEREOF Lothair H. Rowley, Syosset, andWilliam C. Boehm, Jr.,

Middle Village, N.Y., assignors to Sperry Rand Corporation, acorporation of Delaware Application March 2, 1955, Serial No. 491,608Claims. (Cl. 33668) The present invention relates to magnetic cores ofthe type in which a thin continuous magnetic iron strip is woundspirally around a mandrel to form a laminated core and more particularlyto the means for mounting such a core when forming part of a core-coilelectromagnetic assembly.

In producing a core of the type described, a thin continuous magneticiron strip is wound spirally around a rectangular mandrel. The resultingcore may then be bonded with an impregnating material and cut into twoparts, which can then be assembled in such a way as to link a coil orcoils thereto electromagnetically. The core-coil assemblies so producedcan be employed as iron-core inductors, such as transformers andreactors. A typical core of the type described is one sold under thename of Hipersil core.

Hitherto, for mounting a core-coil unit of the type described, abracket, a foot or similar mounting device especially fabricated, wassecured to the core by fastening elements, after it was completelyformed, to secure the core-coil unit in position. This operation wasexpensive and time-consuming and did not always result in a rugged,firm, stable support or mounting for the unit.

One object of the present invention is to apply a mounting device to themagnetic core of the type described by a process, which will assure firmsupport and mounting of the core-coil unit, which is comparativelyinexpensive to carry out, which requires a minimum of time to follow,and which dispenses with the use of elements for fastening the mountingdevices to the core.

Another object of the invention is to provide a magnetic core of thegeneral type described having mounting devices attached thereto in a newand novel manner.

In accordance with certain features of the invention, during the processof winding the continuous magnetic iron strip around the mandrel in theformation of the laminated core, mounting studs or pins are placedagainst an intermediate turn, which is the outside turn at that stage,so that these studs project from the face of the core. The winding isthen continuous around the studs, without a break in the strip, untilthe core is completely Wound for lamination. Since the strip is undertension when wound around the mandrel, the studs become firmly andpermanently embedded into the laminating structure of the core. Thus themounting devices are built into the core during the course of itsmanufacture, thereby cutting down the time required to manufacture thecomplete electromagnetic unit, and reducing the expense of manufacture.At the same time, mounting means are afforded which are rugged andsecure and are able to withstand effectively rough handling andmechanical shock.

Various other objects, features and advantages of the invention areapparent from the following description and from the accompanyingdrawing, in which:

Fig. 1 is a view of a single-phase core after it is wound with mountingdevices in accordance with the present nite States Patent 6 PatentedSept. 29, 1959 invention, said core being shown partly in section andpartly in front face View;

Fig. 2 is a side view of the core shown in Fig. 1;

Fig. 3 is a side view of a stud constituting one of the mounting devicesembodying the present invention;

Fig. 4 is a side view of a core-coil electromagnetic unit having thecore of Fig. 1 as a part thereof and shown in mounted position.

Fig. 5 is a top plan view of the core-coil unit of Fig. 4 in mountedposition;

Fig. 6 is a view of part of the core shown with a modified form ofbuilt-in mounting stud; and

Fig. 7 is a perspective of a 3-phase core after it is wound withmounting devices in accordance with the present invention.

Referring to Figs. 1 to 3 of the drawings, there is shown a magneticlaminated single-phase core 10 adapted to form part of anelectromagnetic core-coil unit. This core is made by spirally andtightly winding under ten sion, a very thin continuous magnetic ironstrip 11, made for example of silicon steel, around a mandrel 12 ofsubstantially rectangular cross section. Somewhere in an intermediatestage of winding, mounting studs, pins or posts 13 are placed againstthe last applied turn at the corners, with their end sections 14projecting from one face of the core, and the winding is continued undertension around said studs, without a break in the strip, until the corelamination is completed. These studs 13 are preferably inserted inposition at a stage which will locate them substantially midway betweenthe inside and the outside la'minations of the core.

The mounting pins or studs 13 may be in the form of tubes or in the formof solid rods as shown in Figs. 1 to 3, and each has preferablyenlargements to define a head 15 at one end and a collar 16 intermediateits ends, integral with the stud. The distance between theseenlargements corresponds to the depth of the core 10, so that theseenlargements engaging opposite faces of the core, serve as shoulders tolocate the stud 13 lengthwise in proper position on the partiallycompleted core during the lamination build-up process and to hold saidstud permanently and rigidly in said position against lengthwisemovement in the completed core. The projecting ends 14 of the stud 13may be shaped and constructed according to the manner in which the finalcore-coil electromagnetic unit is to be mounted. For example,

the projecting ends 14 of the studs 13 may be offset and shaped to formbrackets or feet, or if the studs are hollow they may be straight andmay be internally threaded to receive a screw therein from a supportmember or chassis or may be externally threaded to receive a nut forconnection to such a support member. In the specific form shown in thedrawings, the studs 13 are straight and externally threaded at theirouter ends.

After the lamination winding is completed, the last turn may be anchoredin position as for example by spot welding it in place. The innerlamination is left either unfastened or taped in place depending uponthe material and size of the core. The resulting core 10 will be in theform of a rectangular open frame.

After the core is formed as described, it may be impregnated in asuitable bonding material and cut in order to facilitate assembly of thecore with a coil or coils. Figs. 4 and 5 show the core 10 of Figs. 1 and2 cut along the lines 18 to permit the resulting sections to beseparatedfor assembly with the preformed coil or coils 20. The twosections of the core 10 are brought together,

either in abutting relationship or in spaced relationship,

.in during the final winding stages.

20 and core 10 are assembled as described, then the two parts of thecore are held in position by means of a banding strap 21 wrapped aroundthe core and threaded through a seal 22, the tension being applied tothe strap during this operation by means of a suitable. banding tool.The assembly so formed will have a series of studs 13 as described,projecting from the unit in position to be easily attached to a suitablesupport.

In Fig. 4, the studs 13 are shown extending through a plate 23 which mayconstitute part of a frame structure towhich it is desired to attach thecore-coii'unit. For example, this plate 23 may constitute part of a baseor part of a chassis of an electric apparatus, and the studs passingthrough holes in said plate may be secured in position by means of'nuts24.

In Fig. 6 is shown a modified form of stud 13a having a cross section sodesigned as to eliminate the possibility of its displacement along thelaminations of the core 10a, either during the process of winding orafter the core is completely wound. For that purpose, the stud 13a isshown of somewhat angular cross-section and specifically ofsubstantially right triangular cross-section, to correspondapproximately to the shape of the corner of the core 10a. The stud 13a sshaped, is positioned with the sides bounding the right anglesubstantially parallel to the corresponding sides of the core at thecorner. In all other respects, the stud 13:: may be similar to the stud13 of Figs. 1 to 5.

The stud 13a shaped as described, will seat properly in position betweensuccessive lamination turns during the intermediate winding stage, whenit is first placed upon the partially wound core and will be firmlyretained there- A stud 13a is placed at each corner of the core a, andthe core is made with the studs built therein'in the process of makingthis core, in the manner described in connection with the constructionof Figs. 1 to 5. After the core 10a is completed and forms part of thecore-coil unit as described, the studs 13a will be firmly held inposition, not only against endwise movement by its shoulder formationsabutting opposite faces of the core but also against transverse movementalong the laminations of the core by its angular cross-sectional shape.

Fig. 7 shows the present invention applied to a core 10b of the 3-phasetype. This core comprises twin rectangular laminated core elements 25,formed by continuous strip winding around mandrels, as was described inconnec-.

tion with Figs. 1 to 5, but without the insertion of the studs therein.These twin core elements 25 are then placed side by side and an outsidecore element 26 is wound around these elements 25 by a continuous strip.Before or during the intermediate stage of winding this outer coreelement 26, the studs 13b, similar tothe studs 13 or 13a of Figs. 3 and6 are inserted in the position. In the specific form shown, these studs13b are inserted in position during the intermediate stage of winding ofthe outer core element 26, and the winding of the outer core elementthen continued around these studs. The core 10b can then be finished inthe manner described in connection with the construction of Figs. 1 to3.

It is seen therefore that in all of the forms shown, the studs will bebuilt into the structure of the cores during the process of making thecores and no special attach- I ments are necessary to secure these studsto the cores.

studs are shown located at the corners respectively of the coil, as faras certain aspects of the invention are concerned, the number of studsmay be modified according to the type of mounting required.

While the invention has been described with particular reference tospecific embodiments, it is to be understood that it is not to belimited thereto, but is to be construed broadly and restricted solely bythe scope of the appended clairns. i

What is claimed is:

1. A magnetic iron core of the character described which is adapted tobe cut into two separate U-shaped sections for assembly with apre-formed coil, said core comprising an elongated thin flat strip ofmagnetic material spirally contiguously wound under tension into an openlaminated rectangular frame with the last lamination spot welded inplace, said frame being impregnated with bonding material to preventspreading of the laminations thereof when said frame is cut into twosections, and a plurality of transversely extending mounting studs eachof which is firmly embedded at a corner of'said frame between contiguouslaminations intermediate the innermost and outermost laminations of saidframe, each of said studs having an end projecting outwardly from theface of said frame for anchorage to a supporting member.

2. A magnetic core as defined in claim 1, in which each of said studshas a pair of spaced shoulders engaging opposite faces of said frame tolocate said studs in fixed position against endwise movement in saidframe.

3. A magnetic core as defined in claim 2, in which each of said studs issubstantially triangular in cross section, and in which each of saidstuds is so embedded between said contiguous laminations that two of itsadjacent sides are substantially parallel to two adjacent sides of saidframe at said corner.

4. A magnetic core as defined in claim 1, in which each of said studs issubstantially triangular in cross section, and in which each of saidstuds is so embedded between said contiguous laminations that two of itsadjacent sides are substantially parallel to two adjacent sides of saidframe at said corner.

5. An electromagnetic device comprising an open rectangular magneticiron core cut into two separate opposed U-shaped sections two opposinglegs of which are inserted into a preformed coil and said sectionsbanded together, said core comprising a thin flat strip of magnetic material spirally contiguously wound under tension into an open laminatedrectangular frame with the last lamination spot welded in place, saidframe'being impregnated with bonding material to prevent spreading ofthe laminations thereof when said frame is cut into two sections, and aplurality of transversely extending mounting studs each of which isfirmly embedded at a corner of said frame. between contiguouslaminations intermediate the inner-. most and outermost laminations ofsaid frame, each of said studs having an end projecting outwardly fromthe face of said frame for anchorage to a supporting member.

References Cited in the file of this patent UNITED STATES PATENTS KyleMar. 1, .1955

